In a modern materials handling facility, operational efficiency may be enhanced by increasing the storage density, e.g., the number, volume or mass of items stored at the materials handling facility, on a per-square foot basis. Storage density may be increased in an effective manner relative to the cost of new construction by expanding the capacity of a materials handling facility in a vertical direction, such as by adding one or more fixed or moving shelving systems, which enable the storage of different types of items at different elevations within the materials handling facility. Such shelving systems may include one or more racks, mezzanines, bars, platforms, bins, cabinets, drawers or other like storage units where items may be stored on a temporary basis or for extended durations.
In a materials handling facility, one or more workers typically deposit one or more items into a storage unit, and retrieve such items therefrom at a later time. Therefore, where a materials handling facility includes one or more shelving systems or other vertically mounted or oriented storage units, a worker must change his or her elevation in order to deposit one or more of the items therein, or retrieve one or more of the items therefrom. In the interests of economy, however, many materials handling facilities include shelving systems that feature storage units that are out-of-reach to most humans. For example, in many materials handling facilities such as file storage depots or hardware stores, shelves of nine, thirteen or even fifteen feet in height are common.
In order for a worker to access storage units that are included in one or more shelving systems, a ladder or other platform-like device is typically provided. A ladder may include a variety of steps that may be ascended or descended by a worker in order to place an item within one or more storage units provided on a shelving system, or to access an item that is provided within one or more of the storage units, as well as one or more auxiliary shelves, support rails, steps, hinges, braces or locks. When using a ladder, a worker must typically move the ladder to a convenient location with respect to the shelving system or storage unit in which he or she is interested, open or extend the ladder, before ascending and descending the ladder to access the shelving system or storage unit, e.g., to deposit an item into or retrieve an item from a storage unit, or to otherwise inspect the contents of the storage unit. Subsequently, in order to access another shelving system or storage unit, the worker (or another worker) must typically close or contract the ladder, relocate the ladder to another location associated with that shelving system or storage unit, and open or extend the ladder again, before ascending and descending the ladder to access that shelving system or storage unit.
Depending on the sizes of the shelving systems or storage units with which they are associated, ladders or other platform-like devices may typically occupy a substantial area or volume of a materials handling facility. The requirement to transport and operate a ladder prior to ascending or descending the ladder may tend to hinder their utility and value, and is one of many drawbacks to their widespread use in a materials handling facility.